The objective of the proposed research is to contribute to the understanding of the processes of neuronal integration that occur in the cerebral cortex. This problem will be approached through study of the piriform cortex -- an area which shares many features of organization with the neocortex, but by virtue of its relative simplicity and unique structural characteristics, is very amenable to experimental analysis. The technique of intracellular injection of horseradish peroxidase after physiological study of neurons will be utilized in these experiments. The different populations of neurons in the piriform cortex will be characterized both physiologically and anatomically (with light and electron microscopy). It is hoped that these experiments will not only elucidate the mechanisms by which olfactory information is processed by the piriform cortex but also reveal general principles that will assist in the analysis of neuronal mechanisms in more complex cortical systems.